1. Field of the Invention
The invention generally relates to endoscope pincers and, more particularly, toward rotary endoscope pincers wherein the term xe2x80x9cpincersxe2x80x9d concerns an endoscope implement having mutually displaceable arms and may be considered to be similar to scissors.
2. Description of Related Art
Rotary endoscope pincers of the aforementioned-type are characterized by a pincers head that, together with its actuation rod, can be removed from the remnant pincers. This feature entails a detachable but omni directionally firm connection of the pincers head to the distal tube end. However, because the diameter is very narrow, namely only several millimeters, such a connection can be manufactured only with great difficulty.
As a result, pincers of this kind are fitted with a screw or a bayonet connection between the pincers head and the tube. Such a connection provides adequate mechanical strength even under these constricted circumstances. However, such a connection locks only axially and, therefore, for purposes of reliability, further requires a rotary connector. With regard to pincers of this kind, and in view of the restrictions on space, the rotary connector must be situated in the tube""s proximal end zone between the proximal end zone and the rod, and also must be detachable to allow dismantling.
The literature, and illustratively the European patent documents 0 688 187 B1 and 0 633 002 A1 and the German patent document 198 55305 C1, discloses several possible designs for the proximal rotary connector between the tube and the rod.
But those designs all entail significant drawbacks. On one hand may be grouped those designs that have an exceedingly complex configuration. On the other hand may be grouped those designs requiring a laborious manual operation to disengage the rotary connector.
The present invention is directed toward pincers having a rotary connector providing a simplified design that is easy to operate.
An endoscope pincers according to the present invention includes a transversely displaceable slider situated in the tube""s proximal end zone and crossed within an elongated slot by the rod. The elongated slot comprises two areas, each of which engage the rod when the slider is located in different slider positions. If, in one slider position, the elongated slot engages by its clearance the rod, then it shall loosely enclose the rod by a clear circular cross-section corresponding to the maximum diameter of the proximal rod segment. Accordingly, the rod then can be rotated relative to the slider and, hence, relative to the tube to be freed thereby for the purpose of releasing the pincers head. In this slider position the rod also can be fully removed from the elongated slot or be reinserted into it. As regards the other slider position, the elongated slot, by means of its gripping zone, will rotationally lock onto an engagement zone of the rod presenting rotational asymmetry, the rod being thereby irrotational or fixed against rotation while being longitudinally displaceable. This design involving a simple slider and a simple rotationally asymmetrical rod zone is exceedingly useful in manufacture.
In further accordance with the present invention, the inventive design offers substantial handling advantages. Particularly, the slider can be displaced in a simple and surveyable manner into a position securing and releasing the rotational connector. No other actuations are required.
The tube may be affixed to the terminal structure. Preferably, however, the tube is detachably affixed in a conventional manner to the terminal structure so as to advantageously constitute pincers that are easily cleaned, namely creating pincers that can be resolved into three parts, that is a pincers head with rod, a tube and a terminal structure.
In further accordance with the present invention, a locking device secures the tube to the terminal structure. The locking device is connected to the slider and thereby eliminates the need to separately actuate the locking device. When driving the slider into the rotationally disengaged position, the tube may be unlocked simultaneously or, alternatively, unlocked when in a third site of extension. In this way the design is simplified and actuation is made easier. If the positions for tube disengagement and rotational unlocking coincide at the slider, then, at this slider position, the pincers can be easily separated into its three components.
In further accordance with the present invention, the tube is rotatably affixed to the terminal structure. Such a design, which may be fitted, for instance, with the tube locking device of the German patent document 198 53 305 C1, is preferred in modern pincers wherein the rotational pincers position relative to the terminal structure can be adjusted arbitrarily.
In further accordance with the present invention, the slider is guided in a rotatably fixed manner in the borehole. This ensures that the slider always assumes its appropriate rotational position wherein the elongated slot may be inserted into the rod.
In further accordance with the present invention, the slider is held by the force of a spring in the engaged position of the gripping zone against the rod. This arrangement ensures that, unless deliberately actuated, the slider keeps the pincers in its locked position.